Buggy code:
public class Execute { public static final int INVALID = Integer . MAX_VALUE ; private String [ ] cmdl = null ; private String [ ] env = null ; private int exitValue = Execute . INVALID ; private ExecuteStreamHandler streamHandler ; private ExecuteWatchdog watchdog ; private File workingDirectory = null ; private Project project = null ; private boolean newEnvironment = false ; private boolean useVMLauncher = true ; private static String antWorkingDirectory = System . getProperty ( "user.dir" ) ; private static Execute . CommandLauncher vmLauncher = null ; private static Execute . CommandLauncher shellLauncher = null ; private static Vector procEnvironment = null ; private static ProcessDestroyer processDestroyer = new ProcessDestroyer ( ) ; public static synchronized Vector getProcEnvironment ( ) { } private static String [ ] getProcEnvCommand ( ) { } public static String toString ( ByteArrayOutputStream bos ) { } public Execute ( ) { } public Execute ( ExecuteStreamHandler streamHandler ) { } public Execute ( ExecuteStreamHandler streamHandler , ExecuteWatchdog watchdog ) { } public String [ ] getCommandline ( ) { } public void setCommandline ( String [ ] commandline ) { } public void setNewenvironment ( boolean newenv ) { } public String [ ] getEnvironment ( ) { } public void setEnvironment ( String [ ] env ) { } public void setWorkingDirectory ( File wd ) { } public void setAntRun ( Project project ) throws BuildException { } public void setVMLauncher ( boolean useVMLauncher ) { } public static Process launch ( Project project , String [ ] command , String [ ] env , File dir , boolean useVM ) throws IOException { } public int execute ( ) throws IOException { } protected void waitFor ( Process process ) { } protected void setExitValue ( int value ) { } public int getExitValue ( ) { } public static boolean isFailure ( int exitValue ) { } public boolean killedProcess ( ) { } private String [ ] patchEnvironment ( ) { } public static void runCommand ( Task task , String [ ] cmdline ) throws BuildException { try { task . log ( Commandline . describeCommand ( cmdline ) , MSG_VERBOSE ) ; Execute exe = new Execute ( new LogStreamHandler ( task , Project . MSG_INFO , Project . MSG_ERR ) ) ; exe . setAntRun ( task . getProject ( ) ) ; exe . setCommandline ( cmdline ) ; int retval = exe . execute ( ) ; <START_BUG> if ( retval != 0 ) { <END_BUG> throw new BuildException ( ( ( ( cmdline [ 0 ] ) + "<seq2seq4repair_space>failed<seq2seq4repair_space>with<seq2seq4repair_space>return<seq2seq4repair_space>code<seq2seq4repair_space>" ) + retval ) , task . getLocation ( ) ) ; } } catch ( IOException exc ) { throw new BuildException ( ( ( ( "Could<seq2seq4repair_space>not<seq2seq4repair_space>launch<seq2seq4repair_space>" + ( cmdline [ 0 ] ) ) + ":<seq2seq4repair_space>" ) + exc ) , task . getLocation ( ) ) ; } } private static class CommandLauncher { public Process exec ( Project project , String [ ] cmd , String [ ] env ) throws IOException { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } } private static class Java11CommandLauncher extends Execute . CommandLauncher { public Process exec ( Project project , String [ ] cmd , String [ ] env ) throws IOException { } } private static class Java13CommandLauncher extends Execute . CommandLauncher { public Java13CommandLauncher ( ) throws NoSuchMethodException { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } private Method _execWithCWD ; } private static class CommandLauncherProxy extends Execute . CommandLauncher { CommandLauncherProxy ( Execute . CommandLauncher launcher ) { } public Process exec ( Project project , String [ ] cmd , String [ ] env ) throws IOException { } private Execute . CommandLauncher _launcher ; } private static class OS2CommandLauncher extends Execute . CommandLauncherProxy { OS2CommandLauncher ( Execute . CommandLauncher launcher ) { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } } private static class WinNTCommandLauncher extends Execute . CommandLauncherProxy { WinNTCommandLauncher ( Execute . CommandLauncher launcher ) { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } } private static class MacCommandLauncher extends Execute . CommandLauncherProxy { MacCommandLauncher ( Execute . CommandLauncher launcher ) { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } } private static class ScriptCommandLauncher extends Execute . CommandLauncherProxy { ScriptCommandLauncher ( String script , Execute . CommandLauncher launcher ) { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } private String _script ; } private static class PerlScriptCommandLauncher extends Execute . CommandLauncherProxy { PerlScriptCommandLauncher ( String script , Execute . CommandLauncher launcher ) { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } private String _script ; } private static class VmsCommandLauncher extends Execute . Java13CommandLauncher { public VmsCommandLauncher ( ) throws NoSuchMethodException { } public Process exec ( Project project , String [ ] cmd , String [ ] env ) throws IOException { } public Process exec ( Project project , String [ ] cmd , String [ ] env , File workingDir ) throws IOException { } private File createCommandFile ( String [ ] cmd ) throws IOException { } } }

Fix:
if ( Execute . isFailure ( retval ) ) {